Method of the GPS/BDS/GLO/GAL integrated positioning based on DCB correction

With the development of the four global navigation satellite systems(GNSS), the integrated positioning of four GNSS has become future development trend. A combined positioning algorithmusing four system data with weighted measurement fusionis developed in the paper. Using DCB data provided by IGS, the satellite clock error was corrected for each code. The four GNSS positioning accuracy was analyzed with DCB correction and the influence of setting different PDOP thresholdon positioning accuracy was verified in the conditions of guaranteeing the accuracy. The results showed that the reasonable PDOP threshold should be consideredin the positioning model to improve the positioning accuracy and continuity. And using DCB correction, the RMS of N direction and E direction was obviouslyimproved.